World Clock — Real-Time Clocks for 20+ Cities + Time Zone Comparison
View real-time clocks for 20+ world cities including Seoul, Tokyo, New York, London, Paris, and Sydney. Compare time differences between any two cities instantly, with day/night indicators.
Time Zone Comparison
Click any city card to set it as a comparison city above.
Frequently Asked Questions
Q. What is the time difference between Seoul and New York?
Seoul (KST, UTC+9) is 13 hours ahead of New York (EDT, UTC-4) in summer, and 14 hours ahead in winter (EST, UTC-5).
Q. How many hours ahead is Seoul compared to London?
Seoul (UTC+9) is 8–9 hours ahead of London. During British Summer Time (late March to late October, UTC+1) the difference is 8 hours; otherwise 9 hours.
Q. What is the time difference between Seoul and Los Angeles?
Seoul is 16–17 hours ahead of LA. During PDT (UTC-7) the difference is 16 hours; during PST (UTC-8) it is 17 hours.
Q. Does the tool automatically account for Daylight Saving Time?
Yes. The tool uses the browser's Intl API which automatically reflects current DST rules for every city.
Q. How do I find a good meeting time across time zones?
Use the Time Zone Comparison section. Select two cities and the exact time difference is shown instantly — no manual calculation needed.
Q. What are the day/night indicators based on?
A city shows ☀️ (day) if the local time is between 06:00–20:00, and 🌙 (night) otherwise. Useful for finding business hours overlap.
How to Use
Choose two cities from the dropdowns in the Time Zone Comparison section. The time difference appears instantly.
The city grid below shows live clocks for 20+ cities, refreshing every second.
Click any city card to set it as a comparison city in the section above.
Use the search bar to quickly find any city by name.
Expert Knowledge: World Clock — Real-Time Clocks for 20+ Cities + Time Zone Comparison
World time zones are defined relative to UTC (Coordinated Universal Time). While the globe is nominally divided into 24 zones, some regions use 30- or 45-minute offsets (e.g., India UTC+5:30, Nepal UTC+5:45). Daylight Saving Time (DST) is observed in most of North America and Europe from approximately March to November, shifting clocks forward by one hour. Korea, Japan, and China do not observe DST, so their UTC offset remains constant year-round. When scheduling international calls, always verify the current DST status of each participant's time zone.
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